Screw driven piston pump

ABSTRACT

A fluid pump comprises an electric motor configured to provide a unidirectional rotational output. The fluid pump further comprises a screw drive coupled to the electric motor. The screw drive is configured to convert the unidirectional rotational output of the electric motor into reciprocating motion to linearly reciprocate a piston coupled to the screw drive.

CROSS-REFERNECE TO RELATED APPLICATION

The present application is based on and claims the benefit of U.S. Provisional Patent Application Ser. No. 63/203,697, filed Jul. 28, 2021, the content of which is hereby incorporated by reference in its entirety.

BACKGROUND

Fluid delivery systems are used to delivery fluid from a source location to a delivery location. In some instances, fluid delivery systems include a pump system configured to provide the fluid at desired parameters, such as at desired pressures and desired volumetric rates. Fluid delivery systems are useful for a variety of fluids, for example, paints, primers, finishes, A and B part component fluids, as well as a variety of fluids.

The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background.

SUMMARY

A fluid pump comprises an electric motor configured to provide a unidirectional rotational output. The fluid pump further comprises a screw drive coupled to the electric motor. The screw drive is configured to convert the unidirectional rotational output of the electric motor into reciprocating motion to linearly reciprocate a piston coupled to the screw drive.

This Summary is provided to introduce a selection of concepts in a simplified form that further described below in the Detailed Description. This Summary is not intended to identify key features or essential featured of the claimed subject matter, is not intended to describe each disclosed example or every implementation of the claimed subject matter and is not intended to be used as an aid in determining the scope of the claimed subject matter. Many other novel advantages, features, and relationships will become apparent as this description proceeds. The figures and the description that follow more particularly exemplify illustrative examples.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view showing an example spray pump system.

FIG. 2 is a perspective view showing an example pump system.

FIG. 3 is a sectional view showing an example pump system.

FIG. 4 is a perspective view showing an example pump system.

FIG. 5 is a side view showing an example pump system.

FIG. 6 is a perspective view showing an example pump system assembly in a lowered position.

FIG. 7 is a perspective view showing an example pump system assembly in a raised position.

FIG. 8 is a front view showing an example pump system assembly in a raised position.

FIG. 9 is a perspective view showing an example pump system assembly.

FIG. 10 is a perspective view showing an example pump system assembly.

FIG. 11 is a perspective view showing an example line striper pump system assembly.

FIG. 12 is a perspective view showing an example line striper pump system assembly.

FIG. 13 is a perspective view showing an example pump system assembly.

FIG. 14A-C are diagrammatic views showing example motor-pump configurations.

FIG. 15A-B are diagrammatic views showing example self-reversing assemblies.

FIG. 16 is a partial perspective view, partial diagrammatic view showing an example plural component system.

FIGS. 17A-B (collectively referred to herein as FIG. 17 ) are sectional views showing one example self-reversing assembly.

FIG. 18 is a block diagram showing one example pump system assembly.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Piston paint pumps are sometimes driven via hydraulics or eccentrics. Hydraulic paint pumps are typically driven using a gasoline engine having high torque. However, it may be undesirable to use such a system with the exhaust and weight of the system. Eccentric paint pumps are typically driven using an electric motor which solves at least the exhaust problem. However, eccentric driven paint pumps are limited by torque requirements or bending moments.

In another approach, a linear screw driven pump is used. One example of a linear screw drive for converting rotary to linear motion is a ball screw drive. Stroke length is not limited by torque requirements or bending moments as they are in an eccentric drive and a screw drive is typically more durable than an eccentric drive. The torque required in a linear screw drive is substantially the same at any point along the stroke whereas eccentric drives require more or less torque depending on where the piston is in the stroke. Also, a longer stroke length is desirable because the longer the stroke, the longer the running surfaces, and thus less wear at any given point on the surfaces.

In a screw drive, stroke limits can be detected by number of rotations of the motor rather than using stroke limit sensors (as currently used in hydraulic systems, for example). In a screw-driven pump, additional diagnostics may be able to be done with current sensing during extension stroke versus retraction force including possibly diagnosing valve or seal failures. One limitation of known electric piston pumps is that they cycle too fast to be able to detect any issues like this, but it may be possible to detect issues with a longer stroke length.

With a self-reversing screw, typically used for winding winches and certain types of fishing reel spools, the electric motor only needs to spin one direction which means the power electronics will likely be longer lasting, more efficient, and may be able to be simplified compared to roller screw or ball screw where the motor would have to come to a full stop, reverse, and then get up to full speed again. A standard self-reversing screw mechanism may be more substantial than a roller screw due to the lower effective area of a reversing screw compared to a roller screw. A sub type of self-reversing screw called a ball reverser or self-reversing ball screw, provides a way to have the self-reversing feature, but also have higher effective area and greater efficiency.

The change in direction of the piston in a linear screw-driven pump may not happen as frequently as in other piston pump designs so dead band when the piston changes over may be more noticeable if the piston direction cannot be changed rapidly enough. Therefore, in one example, an accumulator can be added to mitigate some of the dead band on changeover. And/or for example, a return profile of a self-reversing screw nut or the self-reversing screw can be changed to reduce the reversing time of the piston.

In a horizontal orientation, a double acting piston pump may need a biasing valve in both inlet and outlet valve in order to prime properly. Once the pump is primed the biasing valves are not needed in order to maintain proper function. In another example, a self-priming circuit may be implemented to eliminate the need for biasing valves.

FIG. 1 is a side view showing an example spray pump system 10. Pump system 10 as shown includes engine 12, hydraulic system 14 and paint pump 16. Engine 12 powers hydraulic system 14 which includes a hydraulic pump, hydraulic reservoir, hydraulic lines, valves, etc. Hydraulic system 14 provides an alternating hydraulic fluid flow to a hydraulic cylinder of paint pump 16. The alternating hydraulic fluid flow is provided to a hydraulic cylinder between a rod and head port of the cylinder which causes the hydraulic piston in the cylinder to reciprocate. The hydraulic piston is coupled to a paint piston which reciprocates in a cylinder to pump a paint from a reservoir to an outlet.

FIG. 2 is a perspective view showing an example pump system 100. Pump system 100 includes fluid pump 102, motor/screw assembly 104, controller 106, outlet manifold 108, handle 110, and stand 112. Fluid pump 102 pumps fluid, such as paint, from a source through fluid intake 101. Fluid pump 102 then pumps the fluid to outlet manifold 108. A user attaches a fluid applicator, such as a spray gun, and a hose to the outlet manifold 108. As shown, outlet manifold 108 has one outlet and a control valve, in other example, outlet manifold 108 can have a different amount of outlets and/or control valves. In some examples, there is no outlet manifold 108 and fluid pump 102 pumps fluid elsewhere. In some examples, an accumulator is provided downstream of fluid pump 102 (e.g., in outlet manifold 108).

Fluid pump 102 is powered by motor/screw assembly 104. As shown, motor/screw assembly 104 is controlled by controller 106. Controller 106 can include various hardware and software components to control and monitor functions of motor/screw assembly 104. In some examples, controller 106 can diagnose problems with motor/screw assembly 104 and/or fluid pump 102. Controller 106 controls the motor/screw assembly 104 to generate a reciprocating motion that is transferred to fluid pump 102 through coupler 103. In some examples, the reciprocating motion is generated by controller 106 sending commands to alternate motor 104 in a forward and a reverse direction which actuates a screw in a forward and reverse direction to drive a nut in a reciprocating motion. In other examples, the nut is driven in alternating forward and reverse direction which drives the screw in a reciprocating motion. In some examples, the screw and nut are self-reversing such that the motor only actuates in one direction to create the reciprocating motion.

In some examples, motor/screw assembly 104 is battery powered. In other examples, motor/screw assembly b is powered by an AC power source (e.g., a wall outlet). As shown, motor/screw assembly 104 are in the same housing, in other examples, the motor and screw are separate from one another. In one example, motor/screw assembly 104 and controller 106 include a Tritex II® motor available from Curtiss-Wright Corporation.

Handle 110 allows a user to easily carry pump system 100. Stand 112 is used to keep system 100 in an upright or otherwise pumping position. As shown, stand 112 is collapsible to reduce the dimensions of system 100. In other examples, stand 112 is non-collapsible. In some examples, stand 112 is removable from system 100, such that another support structure can be used (e.g., one or more of the carts shown below).

FIG. 3 is a sectional view showing an example pump system 100. Controller 106 is electronically coupled to motor/screw assembly 104. Motor/screw assembly 104 includes screw 104-1, motor 104-2 and nut 104-3. As shown, motor 104-2 drives nut 104-3 as if it were the rotor of the motor, such that the nut rotates about rollers to drive the screw 104-1 linearly. In other examples, motor 104-2 could include a more typical motor assembly where the shaft is coupled to the screw or nut. In one example, screw 104-1 is a ball or roller screw and nut 104-3 is a ball or roller screw nut. In this example, nut 104-3 is driven in an alternating forward and reverse sequence to drive a screw 104-1 in a reciprocating motion.

In one example, screw 104-1 is a self-reversing screw and nut 104-3 is a self-reversing nut. In one example of this, nut 104-3 is driven in a single rotational direction and screw 104-1 is driven in a reciprocating motion within nut 104-3. Or in another example, screw 104-1 is rotationally driven in a single direction while nut 104-3 reciprocates. In one example, nut 104-3 acts as a rotor in a motor. Such examples will be shown in more detail in FIGS. 15A-15B.

As shown in FIG. 3 , fluid pump 102 includes a fluid pump rod 102-1 and a fluid pump head 102-2 (e.g., a piston) coupled to fluid pump rod 102-1. Screw 104-1 couples to fluid pump rod 102-1, of fluid pump 102, via coupler 103. As shown, coupler 103 allows screw 104-1 to drive fluid pump rod 102-1 linearly without necessarily translating rotational motion between screw 104-1 and fluid pump rod 102-1. In some examples, coupler 103 allows or facilitates rotational motion to be translated from screw 104-1 to fluid pump rod 102-1. As fluid pump rod 102-1 reciprocates, paint is drawn through paint intake 101 and pumped to outlet manifold 108 (not shown in FIG. 3 ) or to another location.

FIG. 4 is a perspective view showing an example pump environment 400. As shown, fluid pump system 100 is disposed within a fluid source 160. In this case, fluid source 160 is a five-gallon bucket that holds paint. However, in other examples, fluid source 160 can include other fluid sources as well. For instance, fluid source 160 could include a fifty-five-gallon drum or a one-gallon bucket.

Stand 112 is shown in the extended position such that pump system 100 is supported proximate fluid source 160. Stand 112 includes legs 112-1, arms 112-2 and joints 112-3. As shown, there are three of each of these components. In other examples, there may be a different amount of these components. In one example, to adjust for different fluid sources 160, joint 112-3 can be adjusted such that pump system 100 raises or lowers. In another example, to adjust for different fluid sources 160, the length of legs 112-1 may be changed (e.g., via telescoping or pin locking extensions mechanisms). Similarly, in an example, to adjust for different fluid sources 160, the length of arms 112-2 may be changed (e.g., via telescoping or pin locking extensions devices). In some examples, paint intake 101 can be changed to accommodate the fluid source 160. In some examples, stand 112 couples to fluid source 160.

FIG. 5 is a side view showing an example pump environment 500. Environment 500 includes user 108 and pump system 100. As shown, user 108 is carrying pump system 100 via handle 110. As illustrated, stand 112 is in a retracted or storage position. In one example, environment 500 is substantially to scale where user 108 is six feet tall.

FIGS. 6 and 7 are perspective views showing an example pump system assembly 600 in lowered and raised positions, respectively. Pump system assembly 600 includes an example pump system 100 that is coupled to a cart 200. As shown, cart 200 includes wheels 202, handle 204, pedals 206, extension housing 208, extension tube 210, and mounting bracket 212. Wheels 202 allow for movement of cart 200 and pump system 100. For example, cart 200 is tilted rearward such that wheels 202 support a portion of the weight of cart 200 and pump system 100 and a user can pull handle 204 to move cart 200.

Extension housing 208 and extension tube 210 facilitate the raising and lowering of pump system 100. As shown in FIG. 6 , pump system 100 is in the lowered position. As shown in FIG. 7 , pump system 100 is in the raised position. Pump system 100 can be raised and lowered to exchange out fluid sources 160, for instance. In some examples, pump system 100 is manually raised to a given height by lifting pump system 100 until a mechanism between extension housing 208 and extension tube 210 blocks the pump system 100 at the given height. In some examples the mechanism between extension housing 208 and extension tube 210 include locks. In some examples, pump system 100 is automatically raised to a given height by an actuator. In one example, the actuator includes an electronic linear actuator. In one example, the actuator includes a hydraulic or pneumatic cylinder.

In some examples, lifting pump system 100 causes cart 200 to rearwardly tip. To prevent cart 200 from rearwardly tipping while raising pump system 100, foot pedals 206 are provided such that a user can step on pedal 206 and prevent rearward tipping motion of cart 200. In some examples, foot pedals 206 are textured or shaped to accommodate and prevent a user's foot from slipping from foot pedals 206 while pump system 100 is lifted.

FIG. 8 is a front view showing an example pump system assembly 600 in a raised position. As shown, pump system 100 is coupled to cart 200 via mounting brackets 212. As shown, there are two mounting brackets 212. In other examples, there may be a different number of mounting brackets 212. As shown, extension housing 208 and extension tube 210 allow pump system 100 to be completely above fluid source 160, such that the fluid source 160 can be slid out from the side and replaced with another fluid source 160.

FIG. 9 is a perspective view showing an example pump system assembly 600. Pump system assembly 600 as shown includes pump system 100, cart 602 and fluid source 160. Fluid intake 101, in this example, includes a length of hose such that pump system 100 does not have to be as near to fluid source 160 as in other configurations. The length of intake hose also allows pump system 100 to be in a different orientation relative to paint source 160 (e.g., pump system 100 does not have to be vertically above fluid source 160). As shown, pump system 100 is in a different orientation relative to cart 602 than pump system 100 and cart 200 shown in FIGS. 6 and 7 . This creates a lower center of gravity for the assembly of cart 602 and pump system 100. In some examples, fluid intake 101 can be removed from fluid source 160 and coupled to cart 602 for ease of transportation.

As shown, cart 602 is supported by wheels 606 and handle 604. In other examples, different components may be provided to support cart 602 when in a downward spraying position.

FIG. 10 is a perspective view showing an example pump system assembly 600. As shown, pump system assembly 600 has had fluid intake 101 removed from fluid source 160 and is coupled to cart 602. A user can utilize handle 604 to move assembly 600 about a worksite. In some examples, wheels 606 are large enough such that controller 106 of pump system 100 (nor any other component of pump system 100) contacts the ground when moving assembly 600 across a relatively flat surface.

FIG. 11 is a perspective view showing an example line striper pump system assembly 4400. As shown, assembly 4400 includes engine 4402, hydraulic system 4404, fluid pump 4406, manifold 4408, applicators 4410, cart 4412 and wheels 4414. Cart 4412 and wheels 4414 support engine 4402, hydraulic system 4404, fluid pump 4406 and other components of assembly 4400. Engine 4402 powers hydraulic system 4404 to drive fluid pump 4406. Fluid pump 4406 pumps fluid, such as paint, from a fluid source to manifold 4408 and applicators 4410 which apply one or more lines of fluid, such as lines of paint, on the ground as cart 4412 actuates about a worksite.

FIG. 12 is a perspective view showing an example line striper pump system assembly 1200. Assembly 1200 includes pump system 100, cart 1202, battery 1204 and applicators 1210. Pump system 100 is powered by battery 1202 to pump fluid, such as paint, from fluid source 160 to manifold 108 and applicators 1210. The volume to pump capacity of assembly 1200 is less than the volume the pump capacity of assembly 4400 (i.e., even though the size of assembly 1200 is less than the size of assembly 4400, the pump capacities are similar). Also, the weight to pump capacity of assembly 1200 is less than the weight to pump capacity of assembly 4400 (i.e., even though the weight of assembly 1200 is less than the weight of assembly 4400, the pump capacities are similar).

FIG. 13 is a perspective view showing an example pump system assembly 1400. As shown, pump system 100 is disposed within a housing 1402. Pump system 100, in some examples, is similar to pump systems 100 described above. In some examples, the shown pump system 100 has differences from the other pump systems 100 shown in other figures. Pump system 100 also includes a hose intake 101.

FIGS. 14A-C are diagrammatic views showing example motor-pump configurations 1500, 1520 and 1540 that can be used with pump system 100. Configuration 1500 includes motor 104-2 inline with screw 1502 and piston 1506. Configuration 1520 includes motor 104-2 and belt assembly 1522. Belt assembly 1522 allows motor 104-2 to be alongside of screw 1502. Configuration 1540 includes motor 104-2 and gear assembly 1526. Gear assembly 1526 allows motor 104-2 to be alongside of screw 1502. While motor 104-2 is shown in FIGS. 14A-C, it will be understood that in other examples other examples of an electric motor can be used, such as motor 5502.

FIGS. 15A-B are diagrammatic views showing examples of self-reversing actuators 5500, 5550 that can be used with pump system 100 (e.g., as part of motor/screw assembly 104) and the configurations 1500, 1520, and 1540. Self-reversing actuator 5500 includes motor 5502, coupler 5503, screw 5504, nut 5506, tube 5508, and coupler 5510. As shown, motor 5502 is an electric motor. Motor 5502 couples to screw 5504 via coupler 1503. As motor 5502 rotates, screw 5504 also rotates. Rotation of screw 5504 drives linear motion of nut 5506. Nut 5506 is coupled to tube 5508 such that linear motion of nut 5506 is also translated to tube 5508. Tube 5508 can also be referred to as a piston rod. Tube 5508 includes coupler 5510 that allows for coupling of tube 5508 to a fluid pump, for example, fluid pump 102, such as by coupling to rod 102-1, which can include the use of another coupling mechanism such as coupler 103 shown previously.

As shown, screw 5504 is a self-reversing screw and nut 5506 is a self-reversing nut. This configuration allows screw 5504 to rotate in a single direction, which causes nut 5506 to linearly actuate along the length of threads on screw 5504 in a first direction, then at the end of the threads on screw 5504 reverse to linearly actuate in a second direction along the length of the threads. Thus, nut 5506 is able to linearly reciprocate along the length of threads of screw 5504 by way of unidirectional rotation of screw 5504. In this way, the system can produce reciprocating motion with the use of a unidirectional motor or a motor that is operated to only provide unidirectional rotational output, such as motor 5502.

Self-reversing actuator 5550 includes motor 5502, screw 5554, nut 5556 and coupler 5510. As shown motor 5502 includes stator 5557 and nut 5556, which acts as the rotor. As nut 5556 rotates it drives linear motion of screw 5554. Because both nut 5556 and screw 5554 are self-reversing, motor 5502 only drives nut 5556 in one direction which causes screw 5554 to reciprocate linearly. Thus, screw 5554 is able to linearly reciprocate along the length of nut 5556 by way of unidirectional rotation of nut 5556. In this way, the system produce reciprocating motion with the use of a unidirectional motor or a motor that is operated to only provide unidirectional rotational output, such as motor 5502.

As shown, the threads of screw 5504 and 5554 form a double helix raceway comprising a first thread and a second thread, wherein each thread is of a different handedness. For example, the threads of screws 5504 and 5554 comprise both a right-handed thread and a left-handed thread. Having both a right-handed thread and a left-handed thread allows for linear reciprocation of the nut or the screw (whichever is configured to reciprocate in the particular arrangement) in a first direction and a second direction while rotating the other of the nut or the screw in only a first direction of rotation.

The speed at which a self-reversing system reciprocates is determined by a number of different things. For example, the speed at which nut 5556 (or screw 5504 in system 5500) rotates contributes to the reciprocating speed. Also, the pitch (shown at 5562) of the threads contributes to the reciprocating speed. Also, the return pattern (shown at 5564) contributes to the speed at which the reciprocating motion reverses. As shown (at 5564), there is a short pause in the reversing thread. In other examples, the intersection of the threads could form a sharp profile such that the reversing occurs nearly instantaneously. In other examples, the intersection of the threads (shown at 5564) could be smoothed to some degree such that the reversing occurs quicker than shown, but less than the sharp profile. It will be understood that in some examples, motor 5502 can be used as the motor of motor/screw assembly 104 of pump system 100. Though not shown in FIG. 15A, it will be understood that screw 5504 includes a return pattern which can be similar to return pattern 5564.

FIG. 16 is a perspective view showing one example of a plural component system 1600. Plural component system 1600 includes a plurality of pump systems 100 (shown as 100-1 and 100-2), a plurality of fluid sources 1660 (shown as 1660-1 and 1660-2), a control box 1602, a plurality of communication and power lines 1604 (shown as 1604-1 and 1604-2), internally heated fluid hose 1606, communication line 1608, a plurality of fluid outlet lines 1612 (shown as 1612-1 and 1612-2), a plurality of heating lines 1620 (shown as 1620-1 and 1620-2), and communication line 1622.

Control box 1602 can include display elements 1613 and 1618, input mechanisms 1614 and 1616, power line 1610, and can include an electronics assembly that can include one or more controllers (which may comprise one or more processors or microprocessors), a communication system, memory or data store, as well as various other components, including various hardware and software components. As illustrated, power line 1610 is configured to plug into an AC power source (such as a wall outlet) and to provide power to various components of plural component system 1600. In some examples, control box 1602 may include a power converter to convert AC power to DC, such as in the case where motors of pump systems 100 are DC motors. In other examples, control box 1602 may include a rectifier and a rechargeable battery, which in turn powers the motors of pump systems 1000. Various other power supply configurations are contemplated herein.

Control box 1602 is capable of receiving various inputs and providing various outputs. For example, a user can provide inputs through input mechanisms 1614 or 1616 to control the ratio at which component A and component B of the plural component system are delivered, as well as various other operating parameters of the plural component system 1600 such as a speed of each motor of motor/screw assemblies 104-11 and 104-22, a temperature at which delivery lines of hose 1606 are heated, as well as various other parameters. In other examples, operating parameters may be stored within memory of control box 1602 and can be communicated to other components of plural component system 1600, for example, operating parameters of pump systems 100 can be communicated to controllers 106 via communication and power lines 1604. In other examples, communication between control box 1602 and pump systems 100 may be wireless, in which case lines 1604 may only provide power to pump systems 100.

Display mechanisms 1613 (illustratively shown as a display screen) and 1614 (illustratively shown as a light) can be used to surface various information, such as operating parameter information (e.g., A-B ratio, pressures, temperatures, engine speed, etc.) as well as to surface alerts or other notifications. In some examples, display mechanism 1613 may be a touch screen capable of receiving user touch input.

Each pump system 100 is configured to pump a respective component fluid (e.g., part A or part B) at a variable volumetric rate. As illustrated in FIG. 16 , each pump system 100 is coupled to and disposed within a respective fluid source 1660, each illustratively shown as a fifty-five-gallon drum. As can be seen, each pump system 100 is disposed through a respective bung hole 1661 of each fluid source 1660, such that fluid pump 102 (or at least a portion of fluid pump 102) is disposed within each fluid source 1660. Thus, moving parts (e.g., pump head 102-2 of fluid pump 102) of each pump system 100 are disposed within the fluid source. Pump systems 100 are high pressure pump systems in that they can pressurize fluid up to 3000 pounds per square inch (psi) or more. In other examples, pump systems 100 can pressure fluid within a wide range of psi. The use of pump systems 100 eliminates the need for transfer pumps used in other types of plural component systems.

In the illustrated example, one controller 106 (e.g., 106-1) is a chief and one controller 106 (e.g., 106-2) is a worker, thus forming an asymmetric control communication system. In such an example, the chief controller generates and sends control communication to the worker controller (e.g., via communication line 108, or in other ways) and the worker controller controls one or more components of its respective pump system 100 based on the control communication from the chief controller. In other example, other forms of control communication are contemplated and thus, in other examples, there need not be a chief controller and a worker controller. The two controllers 106-1 and 106-2 communicate via communication line 108, though, in other examples, wireless communication between controllers 106-1 and 106-2 is contemplated. For example, a ratio of component A and component B may be desired. Pump system 100-1 may pump component A from fluid source 1660-1 while pump system 100-2 may pump component B from fluid source 1660-2. The desired ratio may be provided by user input provided through input mechanisms 1614 or 1616 of control box 1602 or may otherwise be stored in a memory of control box 1602. The ratio (or some parameter based on the ratio, such as motor speed, volumetric flow rate, etc.) may be provided to a controller 106 via a communication line 1604, though, in other examples, communication may be wireless. The controller 106 controls the speed of the motor of motor/screw assembly 104 based on the ratio (or based on the parameter based on the ratio). In the case of asymmetric control. The chief controller may control its respective motor based on the ratio (or parameter based on the ratio) and provide control communication (indicative of a parameter of the worker fluid pump system) to the worker controller such that worker controller controls its motor based on the control communication.

Advantageously, where pump system 100 includes a unidirectional electric motor (e.g., 5502) or a motor that provides a unidirectional rotational output (e.g., 5502) and a drive, such as a screw drive (e.g., 5500 or 5550), that translates unidirectional rotational output of the motor into bi-directional linear reciprocation of the pump 102, the volumetric rate of fluid pumped by the pump system 100 can be varied by only varying the rotational speed of the motor.

Operating parameters of each pump system 100, such as speed, pressure, volumetric flow rate, etc. can be detected by various sensors and the sensor signals can be communicated to control box 1602 via respective communication and power lines 1604 or can be communicated wireles sly. These parameters can be used in feedback control of the pump systems 100 to achieve desired mix ratios. Some examples of these sensors will be shown in FIG. 18 .

Pump system 100-1 pumps a first fluid (e.g., component A) at a select rate from fluid source 1660-1 out of outlet 108-1 through outlet delivery line 1612-1 to an inlet 1666-1 of a respective fluid line 1664-1 of hose 106. Pump system 100-2 pumps a second fluid (e.g., component B) at a select rate from fluid source 1660-2 out of outlet 108-2 through outlet delivery line 1612-2 to an inlet 1666-2 of a respective fluid line 1664-2 of hose 106.

Electrical heating lines 1620 are also shown running from control box 1602 to hose 1606. Hose 1606 can comprise two fluid lines 1664 (shown as 1664-1 and 1664-2), each configured to carry and deliver a respective fluid to fluid applicator 1630, such as a plural component spray gun that is coupled to hose 106. Each fluid line 1664 can be internally heated. Each electrical heating line 1620 can be coupled to a respective electrical heating element of a respective fluid line 1664 to internally heat the fluid. The temperature at which the fluid is heated can be controlled by control box 1602, the heating parameter can either be stored in memory or input by a user.

A communication line 1622 can be seen coupled to running from control box 1602 where it may couple, at the other end, to a fluid applicator 1630, such as a spray gun (e.g., plural component spray gun). Activation and deactivation of a trigger of the fluid applicator 1630 may generate an electrical signal which is communicated to control box 1602 via communication line 1622 to activate and deactivate pump systems 100.

FIGS. 17A-B are sectional views showing one example of a self-reversing assembly 6000. Self-reversing assembly 6000 can be similar to the arrangement 5500 shown in FIG. 15A and can be used in the arrangements 1500, 1520, and 1540 shown in FIGS. 14A-14C. Self-reversing assembly 6000 can be used in fluid pump system 100. As shown in FIG. 17 , self-reversing assembly is in the form of a self-reversing ball screw drive that includes a self-reversing ball screw 6004 and self-reversing ball nut 6006. Though not shown in FIG. 17 , self-reversing assembly 6000 can include a motor (e.g., a motor similar to motor 5502 or motor similar to the motor of motor/screw assembly 104, etc.) that is coupled to rod 6070 of self-reversing ball screw 6004 via a coupler (e.g., coupler similar to coupler 5503, etc.) or by a gear assembly (e.g., similar to gear assembly 1526) or by a belt assembly (e.g., similar to belt assembly 1522). Thus, the motor may be inline with self-reversing ball screw drive or may be offset from the self-reversing ball screw drive. Additionally, self-reversing assembly 6000 can include a controller, similar to controller 106.

As illustrated in FIG. 17 , screw 6004 is configured to be rotated by a unidirectional rotational output of the motor to which the screw 6004 is coupled. The rotation of screw 6004 causes liner reciprocation of nut 6006 along the length of screw 6004 via threads 6060. Threads 6060 can be similar to threads 5560 shown in FIG. 15B. As is known in the art, a self-reversing ball nut 6006 can include roller elements, such as ball bearings (not shown), that travel through the raceway defined by the threads 6060 and a mechanism (not shown) to recirculate the roller elements. Nut 6006 also includes a wear ring 6030 around its outer diameter that is in contact with the interior wall of tube 6040. Wear ring 6030 prevents helps reduce wear of nut 6006 by preventing contact between nut 6006 and tube 6040, maintains concentric alignment between nut 6006 and screw 6004, and can absorb side load.

Nut is coupled to a piston rod 6010 by a connection assembly which includes a flange 6018 of piston rod 6010, a plurality of fasteners 6020 (e.g., threaded fasteners) a plurality of apertures 6022 (e.g., threaded apertures) of piston rod 6010, and a plurality of apertures 6024 (e.g., threaded apertures) of nut 6006. Fasteners 6020 are inserted through apertures 6022 and 6024 to secure piston rod 6010 to nut 6006 such that the piston rod 6010 is linearly reciprocated with linear reciprocation of the nut 6006. Piston rod 6010 further includes a coupler 6012 (which can be similar to coupler 5510), a wear ring 6014 around its outer diameter and a cavity 6016. Coupler 6012 allows for coupling of piston rod 6010 to a fluid pump, for example, fluid pump 102, such as by coupling to rod 102-1, which can include the use of another coupling mechanism such as coupler 103 shown previously. As shown in previous FIGS., the rod 102-1 can include a coupler that is similar to coupler 6012 of piston rod 6010. Cavity 6016 defines a space into which screw 6004 and a piston guide 6050 fit such that piston rod 6010 fits around and travels a length of piston guide 6050 and screw 6004. Wear ring helps reduce wear of piston rod 6010 by preventing contact between piston rod 6010 and housing 6080, helps maintain concentric alignment of piston rod 6010, and can also absorb side load.

Piston guide 6050 also helps to maintain concentric alignment of piston rod 6010 and helps prevents contact between piston rod 6010 and screw 6004. Piston guide 6050 is coupled to screw 6004 by a coupling assembly that includes a fastener 6052, an aperture 6052 (e.g., threaded aperture) of screw 6004, and an aperture 6056 of piston guide 6050. Aperture 6056 can include a threaded portion 6058. Fastener 6052 is inserted through apertures 6056 and 6054 to secure piston guide 6050 to screw 6004.

As further illustrated in FIG. 17 , housing 6080 includes a wiper seal element 6090. Wiper seal element prevents environmental debris (e.g., dust, etc.) from entering and interior of housing 6080 and also wipes fluid (e.g., paint, etc.) from the outside diameter of piston rod 6010 such that the fluid is prevented from entering an interior of housing 6080.

Assembly 6000 further includes a bearing assembly 6072, which may include one or more roller elements (e.g., ball bearings, etc.) that assists in the rotation of screw 6004. Assembly 6000 further includes a bearing cap 6074 which helps retain bearing assembly 6072. Bearing cap 6074 is coupled to housing 6080 by a coupling assembly which includes a plurality of fasteners 6076 (e.g., threaded fasteners), a plurality of apertures 6077 (e.g., threaded apertures) of bearing cap 6074, and a plurality of apertures 6081 (e.g., threaded apertures) of housing 6080. Fasteners 6076 are inserted through apertures 6077 and 6081 to secure bearing cap 6074 to housing 6080. Bearing cap 6078 further includes a sealing element 6078 which prevents environmental debris (e.g., dust, etc.) from entering an interior of housing 6080 or from contaminating bearing assembly 6072 and also helps to prevent leaking and thus retain bearing lubricant (e.g., grease, etc.) within bearing assembly 6072.

As further illustrated in FIG. 17 , housing 6080 includes a side portion 6083 that defines sides of housing 6080 as well as a plurality of ends 6085 (shown as a first end and a second end). As can be seen, side portion 6083 further includes a plurality of fasteners 6087 (e.g., threaded stanchions, etc.) which are inserted through respective apertures 6088 of a respective end 6085. A respective fastening mechanism 6089 (e.g., a nut, etc.) secures the ends 6085 to the side portion 6083 by mating with fasteners 6087.

FIG. 17A shows the piston rod in an extended (e.g., downstroke) position and FIG. 17B shows the piston rod in a retracted (e.g., upstroke) position. Thus, nut 6006 linearly travels in a first direction (e.g., extending or downstroke direction) and a second direction (e.g., retracting or upstroke direction) by unidirectional rotation of the motor and screw 6004.

It will be understood that the assembly 6000 can comprise various materials, some examples of which are listed. The bearing assembly 6072 can comprise a metal, such as steel. The bearing cap 6074 can comprise a metal, such as aluminum. The housing 6080 can comprise a metal, or different parts of the housing 6080 can be made of different materials, such as different metals. For example, fasteners 6087 can comprise steel whereas side portion 6083 and ends 6085 can comprise steel or aluminum. The self-reversing ball nut 6606 can comprise metal, such as steel with steel roller elements (e.g., steel ball bearings, etc.). The self-reversing ball screw 6604 can comprise metal, such as steel. Piston guide 6010 can comprise, for example, acetal resin. Wiper sealing element 6090 can comprise a nitrile rubber or fluoroelastomer. Sealing element 6078 can comprise nitrile rubber or fluoroelastomer. Piston rod 6010 can comprise a metal, such as steel. Tube 6040 can comprise a metal, such as steel. Various other materials are contemplated herein.

FIG. 18 is a block diagram showing one example of a fluid pump system 1100. Fluid pump system 1100, in one example, can be similar to fluid pump system 100. Fluid pump system 1100 includes motor 1102, drive 1104, pump 1106, inlet 1108, outlet 1110, coupler 1111, controller 1112, communication circuitry 1114, one or more power sources 1116, one or more interface mechanism(s) 1118, one or more sensors 1120, handle 1122, stand 1124, cart 1126, one or more housings 1128, one or more hoses 1130, connection assembly 1132, as well as various other items 1150.

Motor 1102 can be similar to other motors described and/or shown herein (e.g., motor of motor/screw drive assembly 104, motor 5502, etc.). Motor 1102 can be an electric bidirectional motor or an electric unidirectional motor. In one particular example, motor 1102 can be a unidirectional electric motor that provides a unidirectional rotational output. Drive 1104 can be similar to other drives described and/or shown herein (e.g., screw drive of motor/screw drive assembly 104, screw drive 5500, screw drive 5550, screw drive 6000, etc.). Drive 1104 is coupled to motor 1102 and configured to convert the rotational output of motor 1102 into linear and bidirectional (reciprocating) motion. Pump 1106 can be similar to other pumps described and/or shown herein (e.g., pump 102, etc.) and can include a rod (e.g., pump rod 102-1, such as a piston rod) and a pump head (e.g., pump head 102-2, such as a piston). Pump 1106 is coupled to drive 1104 and is driven linearly and bidirectionally (reciprocally) by the rotational output of motor 1102 by virtue of its coupling to drive 1104. Pump 1106 draws fluid (e.g., paint, etc.) through inlet 1108 (e.g., during an upstroke) and expels fluid through outlet 1110 (e.g., during a downstroke). Inlet 1108 can be similar to other inlets described and/or shown herein (e.g., inlet 101). Outlet 1110 can be similar to other outlets described and/or shown herein (e.g., outlet 108).

As shown elsewhere herein, both drive 1104 and pump 1106 can include a coupling feature which form a shoulder and/or surface for the purpose of coupling drive 1104 to pump 1106, some examples of which are shown in FIGS. 3 , FIGS. 14A-C, FIGS. 15A-B, and FIG. 16 . Additionally, pump system 1100 includes a coupler 1111 which removably couples and secures drive 1104 to pump 1106. Coupler 1111 can be similar to coupler 103. Coupler 1111 fits over the coupling feature of both the drive 1104 and pump 1106. In some examples, the coupling feature of drive 1104 is part of the screw (as shown in some previous FIGS., such as 5510 of FIG. 15B or the example shown in FIG. 3 ) and in other examples, drive 1104 further includes a piston rod or tube which includes the coupling feature (as shown in some previous FIGS., such as 5510 of FIG. 15A, 6012 of FIG. 17 , etc.). In one example, coupler 1111 couples the drive 1104 to the pump 1106 by way of the coupling feature of the drive 1104 and the coupling feature of the pump 1106.

Controller 1112 can be similar to other controllers described and/or shown herein (e.g., controller 106). Controller 1112 generates control signals to control the rotation (e.g., speed and/or direction of rotation) of motor 1102. In one example, controller 1112 can be a chief controller that generates control communication that is sent, via communication circuitry 1114, to other fluid pump systems 1104. In one example, controller 1112 can be a worker controller that receives control communication from another chief controller of another pump system 1104. In such an example, controller 1112 generates control signals based on the control communication received from the chief controller of the other pump system 1104. Controller 1112 can include a combination of hardware, firmware, and software. In one example, controller 1112 includes one or more processors and memory storing instructions that are executable by the one or more processors.

As illustrated in FIG. 18 , fluid pump system 1100 can communicate with various other system(s) or device(s). For example, communication circuitry can include wired communication circuitry (e.g., communication wiring) and/or wireless communication circuitry (e.g., wireless transmitter and receiver) that enables fluid pump system 1100 to send and receive communication from various other system(s) and/or device(s). In the illustrated example, fluid pump system 1100 can communicate with one or more other fluid pump system(s) 1160 and/or with one or more remote devices 1170. The communication can be wired, as illustrated by arrows in FIG. 18 . The communication can be wireless, such as over network 1180 which can comprise any suitable or combination of suitable wireless communication network(s), such as the Internet, Bluetooth, etc. Remote devices can be a wide variety of different types of remote devices, such as remote computing devices, for example, handheld mobile computing devices (e.g., smart phone, tablet, handheld control devices, etc.), control boxes (e.g., similar to control box 1602), as well as computer stations or a server. In this way, operating parameters, status, and diagnostics of pump system 1100 can be output to one or more remote devices 1170, such as for display. Additionally, in some examples, control communication can be provided from one or more remote devices 1170 and provided to fluid pump system 1100 and can be utilized by controller 1112 to generate control signals to control the operation of fluid pump system 1100.

Fluid pump system 1100 can include one or more power sources 1116, for example, one or more batteries and/or a wired power source, such as a power cord configured to be plugged into a wall outlet. Power source(s) 1116 can provide power to one or more items of fluid pump system 1100. Fluid pump system 1100 can also include one or more user interface mechanism(s) 1118 which can include a display and/or one or more user input mechanisms. User interface mechanisms 1118 can thus display various information, such as the status, operating parameters, and diagnostics of fluid pump system 1100 as well as receive user inputs, such as user inputs that adjust the operation of fluid pump system 1100. Thus, controller 1112, in some examples, can generate control signals to control the operation of fluid pump system 1100 based on user input received through user interface mechanism(s) 1118. The user input mechanisms can include dials, switches, buttons, or, in the case where a user interface mechanism 1118 is a touchscreen, the user input mechanisms can include surfaced, and touch enabled, buttons. Various other types of user input mechanisms are contemplated.

Handle 1122 can be similar to other handles described and/or shown herein (e.g., handle 110, etc.). Stand 1124 can be similar to other stands described and/or shown herein (e.g., stand 112, etc.). Cart 1126 can be similar to other carts described and/or shown herein (e.g., cart 200, cart 602, cart 1202, cart 4412, etc.).

Fluid pump system 1100 can include one or more housings 1128 which house one or more components of fluid pump 1100, such as the housings shown in previous FIGS. (e.g., FIGS. 2, 3, and 17 ). The one or more housing 1128 can house motor 1102, drive 1104, pump 1106, and controller 1106. In some examples, fluid pump system 1100 can include a hose 1130 coupled to outlet 1110 (e.g., as shown in FIG. 16 ). In some examples, inlet 1108 can include a hose 1130 (e.g., as shown in FIGS. 9-13 )

Fluid pump system 1100 can include a connection assembly 1132 that couples motor 1102 to drive 1104. Connection assembly can be similar to other connection assemblies described and/or shown herein (e.g., belt assembly 1522, gear assembly 1526, coupler 5503, etc.). In other examples, a component of drive 1104 can act as a component of motor 1102, such as the example shown in FIG. 15B where nut 5556 acts as a rotor of motor 5502. As previously described herein, motor 1102 can be offset from drive 1104 and pump 1106. In other examples, as previously described herein, motor 1102 can be inline with drive 1104 and pump 1106.

Sensors 1120 can include a motor speed sensor 1140, a fluid pressure sensor 1142, a flow rate sensor 1144, as well as various other sensors 1146. Motor speed sensor 1140 detects the speed (e.g., revolutions per minute (RPM)) of motor 1102. Such sensors are known in the art and thus are not described in further detail herein. The speed of motor 1102, detected by motor speed sensor 1140, can be output to controller 1112, such as for the purpose of feedback-based (e.g., closed loop) control of motor 1102 and/or can be output to other devices (e.g., 1170) and/or systems (e.g., 1160). For example, there may be motor speed value at which motor 1102 is to operate (e.g., a motor speed setpoint). Controller 1112 may utilize the motor speed setpoint to control operation of motor 1102 and utilize the detected motor speed to adjust the control of motor 1102 during operation.

Fluid pressure sensor 1142 detects the pressure at which fluid is pressurized by the fluid pump system 1100. Such sensors are known in the art and are thus not described in further detail herein. The fluid pressure sensor 1142 can placed at the outlet 1108, or in another location. The fluid pressure, detected by fluid pressure sensor 1142, can be output to controller 1112, such as for the purpose of feedback-based (e.g., closed loop) control of motor 1102 and/or can be output to other devices (e.g., 1170) and/or system (e.g., 1160). For example, there may be a fluid pressure value (e.g., a fluid pressure setpoint) that establishes a desired pressure at which fluid pump system 1100 is to pressurize fluid. Controller 1112 may utilize the fluid pressure setpoint to control operation of motor 1102 and utilize the detected fluid pressure to adjust the control of motor 1102 during operation. For instance, reducing the speed of motor 1102 may in turn reduce the pressure and increasing the speed of motor 1102 may in turn increase the pressure.

Flow rate sensor 1144 detects a volumetric rate at which fluid is output by fluid pump system 1100. Such sensors are known in the art and are thus not described in further detail herein. The flow rate sensor can be placed at the outlet 1108, or in another location. The volumetric flow rate, detected by flow rate sensor 1142, can be output to controller 1112, such as for the purpose of feedback-based (e.g., close loop) control of motor 1102 and/or can be output to other devices (e.g., 1170) and/or system (e.g., 1160). For example, there may be a flow rate value (e.g., a flow rate setpoint) that establishes a desired flow rate at which fluid pump system 1100 is to output fluid. Controller 1112 may utilize the flow rate setpoint to control operation of motor 1102 and utilize the detected flow rate to adjust the control of motor 1102 during operation. For instance, reducing the speed of motor 1102 may in turn reduce the flow rate of fluid output by fluid pump system 1106 and increasing the speed of motor 1102 may in turn increase the flow rate of fluid output by fluid pump system 1106.

Additionally, the viscosity of fluid pumped by pump system 1106 may vary during operation, such as due to temperature change throughout the operation. The change in viscosity may be reflected by the detected motor speed, the detected pressure, and/or the detected flow rate. Thus, advantageously, fluid pump system 1106 can account for the changes in viscosity of the fluid by utilized feedback-based control to adjust the operation of the motor 1102.

Alternatively, or in addition to using the data generated by sensors 1120 for control, controller 1112 or remote devices 1170, or both, may use the sensor data for diagnostics. For example, where motor 1102 is unidirectional and drive 1104 is a self-reversing screw drive, the speed of motor 1140 (in combination with the known dimensions of drive 1104) can be used to track stroke count of the pump 1106. Stroke count can refer to the number of times pump 1106 has cycled through an upstroke and downstroke. The stroke count can be used to track the wear and usage of the fluid pump system 1100, as well as to estimate other metrics, such as volumetric output. In another example, the sensor data can be used to detect potential wear or other malfunction, as part of the diagnostics. For example, variance of the detected flow rate or the detected fluid pressure vary (e.g., by a threshold amount) from an expected flow rate or fluid pressure, can indicate and be used to determine malfunction or wear of fluid pump system 1100. For example, such variance may indicate the existence of a leak, clogging, wear of pump parts (e.g., pump head 102-2), as well as various other wear or malfunction. Similarly, variance of the detected motor speed (e.g., by a threshold amount) from an expected motor speed can indicated and be used to determine malfunction or wear of fluid pump system 1100. For example, such variance may indicate slip due to wear of parts of drive 1104 or wear of parts of drive 1104 or pump 1106 which causes increased load on motor 1102. The diagnostics information can be surfaced on an interface mechanism, such as a display and can be stored for later reference. Additionally, in some examples, where wear or malfunction is determined, an alert or other notification can be output and surfaced on an interface mechanism.

Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. 

What is claimed is:
 1. A fluid pump system comprising: an electric motor configured to provide a unidirectional rotational output; and a screw drive coupled to the electric motor, the screw drive configured to convert the unidirectional rotational output of the electric motor into reciprocating motion to linearly reciprocate a piston coupled to the screw drive.
 2. The fluid system of claim 1, wherein the electric motor, the screw drive, and the piston are inline.
 3. The fluid pump of claim 1, wherein the electric motor is offset from the screw drive, the fluid pump further comprising a set of gears that couples the offset electric motor to the screw drive.
 4. The fluid pump of claim 1, wherein the electric motor is offset from the screw drive, the fluid pump further comprising a belt assembly that couples the offset electric motor to the screw drive.
 5. The fluid pump of claim 1, wherein the screw drive comprises: a rotatable element configured to be rotatably driven by the unidirectional rotational output of the electric motor; and a reciprocating element configured to be driven reciprocally and linearly along the rotatable element by rotation of the rotatable element, the linear element coupled to the piston.
 6. The fluid pump of claim 1, wherein the screw drive comprises: a self-reversing screw having a double helix raceway comprising a first thread and a second thread, wherein the first thread is of a different handedness than the second thread; and a nut.
 7. The fluid pump of claim 6, wherein the self-reversing screw is configured to be rotatably driven by the unidirectional rotational output of the electric motor and wherein the nut is configured to be moved reciprocally and linearly along the self-reversing screw by the rotation of the self-reversing screw, the nut coupled to the piston.
 8. The fluid pump of claim 6, wherein the nut is configured to be rotatably driven by the unidirectional rotational output of the electric motor and wherein self-reversing screw is configured to move reciprocally and linearly along the nut by the rotation of the nut, the screw coupled to the piston.
 9. The fluid pump of claim 1 and further comprising: a controller configured to control rotation of the electric motor.
 10. The fluid pump of claim 1 and further comprising: a fluid inlet configured through which a fluid is drawn into the pump by the motion of the pump rod; and a fluid outlet through which the fluid in the pump is expelled by the motion of the pump rod.
 11. A plural component system comprising: a first fluid source configured to contain a first fluid; a second fluid source configured to contain a second fluid; a first fluid pump system configured to pump the first fluid from the first fluid source, the first fluid pump comprising: a first controller; a first electric motor configured to generate a unidirectional rotational output; a first screw drive, coupled to the electric motor, configured to convert the unidirectional rotational output of the first electric motor into reciprocating motion; and a first pump rod coupled to the first screw drive and configured to be driven by the reciprocating motion of the first screw drive; and a second fluid pump system configured to pump the second fluid from the second fluid source, the second fluid pump comprising: a second controller; a second electric motor that generates a unidirectional rotational output; a second screw drive, coupled to the second electric motor, that converts the unidirectional rotational output of the second electric motor into reciprocating motion; and a second pump rod coupled to the second screw drive and driven by the reciprocating motion of the second screw drive.
 12. The plural component system of claim 11, wherein the first fluid source comprises a first 55-gallon drum and the second fluid source comprises a second 55-gallon drum.
 13. The plural component system of claim 12, wherein the first fluid pump system further comprises a first piston housing portion configured to house the first piston and wherein at least a portion of the first piston housing portion is configured to be disposed within the first fluid source during operation of the first fluid pump and wherein the second fluid pump further comprises a second piston housing portion configured to house the second piston and wherein at least a portion of the second piston housing portion is configured to be disposed within the second fluid source during operation of the second fluid pump.
 14. The plural component system of claim 11, wherein the first screw drive comprises a first nut and a first self-reversing screw, wherein one of the first nut and the first self-reversing screw is configured to be rotated by the unidirectional rotational output of the first electric motor to linearly and reciprocally drive the other; and wherein the second screw drive comprises a second nut and a second self-reversing screw, wherein one of the second nut and the second self-reversing screw is configured to be rotated by the unidirectional rotational output of the second electric motor to linearly and reciprocally drive the other.
 15. The plural component system of claim 11, wherein the first controller comprises a chief controller and the second controller comprises a worker controller, wherein the chief controller sends control communication to the worker controller, the worker controller configured to generate a control signal to control rotation of the second electric motor based on the control communication sent by the chief controller.
 16. The plural component system of claim 11, wherein the first fluid pump is mounted to the first fluid source, the first piston being disposed within an interior of the first fluid source and wherein the second fluid pump is mounted to the second fluid source, the second piston being disposed within an interior of the second fluid source.
 17. The plural component system of claim 11, wherein the first fluid pump can pressurize the first fluid up to at least 3000 pounds per square inch (PSI) and wherein the second fluid pump can pressurize the second fluid up to at least 3000 PSI.
 18. A fluid pump system comprising: a unidirectional electric motor configured to generate a unidirectional rotational output; a drive comprising: a rotational element that is configured to be rotated by the unidirectional rotational output of the unidirectional electric motor; a reciprocating element that is configured to be driven reciprocally along the rotational element by the rotation of the rotational element; a fluid pump comprising: a piston rod coupled to the reciprocating element; and a piston coupled to the piston rod, the piston rod configured to be reciprocally driven by reciprocation of the reciprocating element; a fluid inlet through which fluid is drawn by reciprocation of the piston; a fluid outlet through which fluid is expelled by reciprocation of the piston; and a controller configured to control rotation of the electric motor.
 19. The fluid pump system of claim 20, wherein the rotational element comprises a nut and the reciprocating element comprises a self-reversing screw, the self-reversing screw including a coupling feature that provides a shoulder to retain a coupling mechanism that couples the piston rod to the self-reversing screw.
 20. The fluid pump system of claim 20, wherein the rotational element comprises a self-reversing screw and the reciprocating element comprises a nut, the nut coupled to a piston rod of the drive, the piston rod of the drive including a coupling feature that provides a shoulder to retain a coupling mechanism that couples the piston rod of the pump to the nut. 